This invention relates, generally, to a cargo tie down system wherein chains are used to tie down cargoes on the decks of cargo transport vehicles and to novel chain retainers used in the system. The invention has a particular relation to tying down cargo in the form of rectangular stacks of plates or sheets, such as steel plates, on the decks of railway flatcars that have a series of longitudinally spaced open channels extending transversely across the decks in which tie down chains are stowed when not in use.
In the past, chains have been used to tie down cargos, including rectangular stacks of steel plates and the like, on the decks of railway flatcars in the surfaces of which transverse channels are located. Heretofore, each such channel has been provided with lengths of chain one end of which has been secured in the channel with the chains being stowed or laid in the channels when not in use. In use, the lengths of chain are brought up on opposite sides of the cargo and the free ends secured together using a ratchet load binder and a tensioner.
It will be understood that the sizes of various cargoes with respect to both height and width may vary, thereby requiring that the lengths of chain used be sufficiently long so as to accommodate maximum sized cargoes. It is customary to permanently attach the lengths of chains at one end of each to the interiors of the transverse channels so that they cannot be removed but will be readily available for use when required and stowable in the channels when not in use.
For optimum results, particularly when a cargo is in a form of a rectangular stack of sheets or plates laid one on top of another, the bottom end of each length of chain should be placed at least approximately directly underneath one of opposite sides of the cargo so that when the length of chain is pulled taut it will be juxtaposed to the adjacent side of the cargo being tied down. In order to provide for such juxtaposed placement, it will be necessary to secure some form of chain retainer in the transverse deck channels. This requirement can be met either by providing the channels with a plurality of spaced chain retainers or with an arrangement for temporarily positioning a movable chain retainer in different locations in a channel. In either arrangement, it is a practical requirement that the portion of a given length of chain that is in use in tying down a cargo be readily adjustable so that the bottom end of the active length of chain outside of a channel can be readily inserted and removed from its chain retainer.
In view of the foregoing, the object of the invention, generally stated, is the provision of a new and improved cargo tie down system utilizing lengths of chain for tying down the cargo on the decks of cargo transport vehicles, particularly railway flatcars, the decks of which have a plurality of transverse channels in which tie down chains can be stowed when not in use.
An important object of the invention is the provision of new and improved chain retainers which will be secured in the transverse channels in the decks of cargo transport vehicles, such as railway flatcars, and in which selected links of cargo tie down chain may be readily inserted and removed but which will be firmly secured when upward tension is placed on an active length of chain which is being used in tying down cargo.